Refrigerating apparatus



Y Oct. 19, 193 7. r I H. a. HULL :1- AL, Z ,09 6Q54 3 REFRIGERATING APPARATUS Original Filed Oct. 31, 1931 7 Sheets-Sheet 1 ATTORNEYS INVQENTBOR BY 4 Oct. 19., 1937. H. B. HULL Er'AL 2,096,543

A REFRI'GERATING APPARATUS 7 Original FiledOct. 31, 1931 7 Sheets-Sheet 2 iuvsmcgs 4 1 JATII'QRNEYS w Oct. 19, 1937. H B.- Huu. EI'YAL" 2, A REFRIGERATING APPARATUS I Original Filed Oct. :51, 1931 7.Sheets-Sheet I5 Oct. 19, 1937. H. B. HULL ET AL 2,096,543

" REFRIGERATING APPARATUS Original Filed Oct. 31, 1951 v 7 Sheets-Sheet 4.

l l J I I IINVENTORS ATTORNEYS Oct. 19, 1937. H. B. HULL ET AL REFRIGERATING APPA RA'I'US Original Filed Oct. 31, 1931 7 Sheets-Sheet 6 INVENTOR 6 BY W MW. 4E ATTORNEYSW Oct. 19, 1937. H. B. HULL ET AL 2,096,543

REFRIGERATING APPARATUS Original Filed Oct 33,, 1.951 7 Sheets-Sheet 7 u wuuuuws 44".!- 8469 4-0 I wk \W V 1 4 A if? i \ZZ.

INVENTOR SI BY. 2 1c Patented Oct. 19, 1937 nnrmonna'rmo l rmaa'rus Harry B. null and Alex A. McCormack, Dayton;

Ohio eral aware assignors. by mesne assignments, to Gen- Motors Corporation, a corporation of Del- Application October 31, 1931, Serial N 572,388 Renewed October 29, 1935 3 Claims. (Cl. ass-.176)

This invention relates to refrigerating apparatus and more particularly to sealed motor com- Pressor units.

The objects of our invention include a provision of a sealed motor-compressor unit having an improved unloading means for facilitating the starting of the compressor, improved lubricating means, and improved means for sealing the compressor for preventing the flow of refrigerant from the high pressure portion of the compressor to the low pressure portions.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accom- 15 Denying drawings, wherein a preferred form of the present invention is clearly shown.

In the drawings:

Fig. 1 is a view of a refrigerating system including a sealed motor compressor unit;

30 Fig. 2 is a sectional view of the sealed motor compressor unit shown in Fig. 1;

Fig. 3 is a fragmentary end view of the motor,

compressor unit shown in Fig. 2;

Fig. 4 is a sectional view along the lines fl4 of Fig. 3;

Fig. 5 is a sectional view of a modified form of scaled motor-compressor unit; 4

Fig. 6 is a sectional view of a sealed motor compressor unit of another modified form of sealed w i; Fig. 9 is a section along the line 9.9 of Fig. 7;

Fig. 10 is a section along the line ifi-Hl of Fig. 9;

Fig. 11 is a view looking at the left side of the cylinder shown in Fig. 8, and

43 Fig. 12 is a fragmentary sectional view of another modified form of the invention.

Referring to the drawings and more particularly to Fig. 1, there is shown for the purposes of illustrating the invention a sealed motor-com- ...a pressor unit 20 containing an electric motor and a compressor which compresses the refrigerant and forwards the compressed refrigerant through the conduit 2i to an air cooled condenser 22 where the compressed refrigerant is condensed by the 55 air blown thereover by the fan 23 driven by the fan motor 24. The condensed refrigerant blows down through the condenser 22 and collects in the receiver 25 located below the condenser. From the receiver the condensed or liqu'efled refrigerant is forwarded through the conduit 26 5 to an evaporator 21 which is preferably of the type shown in the patent to R. G. Osborn, 1,556,708. filed October 3, 1923. The liquid re-- frigerant in the evaporator 21 evaporates because of the absorption ofhe'at and is returned to the l compressor through the return conduit 28.

Any suitable means may be employed for controlling the operation of the electric compressor motor and the electric fan motor 24. For the purposes of illustration we have shown a low pressure control in which a bellows 28 is connected by the conduit 30 to the return conduit 28 so that it is responsive to the pressure of the refrigerant and consequently the temperature of the evaporator 21. The pressure responsive bellows 28 operates a snap switch mechanism 3| which opens and closes the electric contacts 32 according to the pressure and consequently the temperature of the evaporator 21. By means of this control mechanism the electric compressor motor and the electric fan motor are caused to operate when the temperature of the evaporator is relatively high and are caused to cease operating when the temperature of the evaporator 21 has become relatively low.

Referring now to Fig. 2 for the details of the motor-compressor unit 28 shown in Fig. 1, there is shown a cylindrical shaped casting 38 provided with a central supporting plate ti and the end supporting plates 38 and 39. A cover plate 5 it is provided at one end of the sealed unit and seals its end of the sealed unit by clamping a suitable lead gasket Al by means of the clamping screws 82 which are threaded into bosses 48 upon the cylindrical casting 36. The opposite end of 4 the sealed unit is sealed by means of the lead gasket 44 which is clamped by a suitable clamping ring 45 which in turn is secured by means of the screws 46 and the bosses I! to a cylindrical portion 36 of the sealed unit 20. 45

The electric motor 50 is positioned between the central plate 3'! and the end plate 88. This motor 50 has a stator 5| which fits into the cylindrical casting 36 and is held thereby as well as by the long bolts 52 which pass through the 50 center plate 31, stator II and are threaded into the end plate 38. The stator SI of the electric motor is supplied with electric current through the lead in bushings 98. The rotor 53 of the electric motor is preferably of the squirrel cage 55 type and mounted upon the rotor shaft 54 which is rotatably mounted within the bearings 55 and 56 fixed within the bearing mountings 51 and 58 while are supported respectively by the end plate 38 and the central plate 31. A crank 59 is fastened to one end of the rotor shaft 54 on the opposite side of the plate 31 from the electric motor 59 by means of the Woodrufi key 69 and the screw 6I. The crank 59 is provided with a crank pin 62 upon which a piston 63 is rotatably mounted. The piston 63 extends into the cylin der 64 which is rotatably mounted in a bearing 65 mounted in the bearing housing 66 which is cast integral with the end plate 39. A counterbalance 68 is provided upon the crank oppositev the crank pin 62 and is of .such a mass as to counterbalance the mass of the crank pin, crank arm and the unbalanced mass of the piston 63. As is evident from Fig. 2, the rotor shaft 54 and the cylinder 64 are mounted eccentrically with respect to each other. That is, the shaft 54 and the rotatable cylinder 64 are not in alignment with respect to the axis of .rotation of each. It will thus be understood that when the shaft 54 is rotated by the electric motor 59, the crank pin 62, the piston 63, and also the cylinder 64 will be revolved, but inasmuch as the cylinder 64 rotates on a difierent axis than the crank pin 62,

the piston 63 will be caused to reciprocate within the cylinder 64 while being revolved.

The refrigerant gas from the return conduit 28 enters the sealed unit through the threaded connection 12 which projects from the plate 13 which covers a check valve 69 (see Fig. 4) located within the end plate 39. From the check valve 69 the refrigerant gas to be compressed is conducted through passage I99 (see Fig. 4) in the bearing housing 66 to a groove 14 in the end of the face of the bearing housing 66. A port 15 is provided in the cylinder wall of the cylinder 64 which registers at proper times with the semicircular groove 14 to admit refrigerant gas to.

-by the reciprocation of the piston 63 therein and forced through the automatic discharge valve 16 into the interior of a sealed unit. 29.

The bearings within the sealed unit are lubricated by means of a force feed lubrication'system in which the lubricant collects at the bottom of the sealed unit, is strained by the conical strainer 18, and drawn up through the passage 19 in the end plate 39 by an eccentric pump 89,

\ which is mounted upon eccentric 8I at the end 'of the shaft 82, which projects from the rotatable cylinder 64. The pump dischargesdnto'the chamber 83 from which point lubricant is forced through the passage 84 in the cylinder shaft 82 to a concentric groove 85 in the lower portion of the wall of the cylinder 64-. From the groove 85 lubricant is conducted .through a passage 86 to a passage 81 within the rotor shaft 54 which passage supplies lubricant to the bearing 56 by means of an oil groove 88. Lubricant is supplied from the passage 81 to the bearing 55 by means of the chamber containing .the spring 96 and the passage 89. t I

An oil operated unloading device is provided for facilitating the starting of the compressor. A passage 99 leads from the pump chamber 83 to an unloading chamber 9I which is provided with a sylphon bellows 92 therein. The bellows 92 operates a suitable unloading valve I9I (see 18. 3) by means of a walking beam construction 93 to allow high pressure gas from the inoperate under normal conditions. An oil pres-' sure relief valve 95 is provided at the opposite end of the compressor to prevent the oil pressure from becoming too high during operating conditions. A spring 96 is provided within a chamber at this end of the rotor shaft to force the rotor shaft toward the .compressor and to maintain the' sealing surfaces between the end of the crank and the end of the bearing housing 66 and the cylinder 64 to prevent the escape of f lubricant and to prevent the high pressure gas from entering the low pressure portions of the compressor. v

InFig. 5 there is shown a sealedunit I29 having a cylindrical shaped casting. I2I and the supporting plates I22 and I23 mounted within recesses at either end of the casting. A dome shaped cover I24 is provided at one end of the cylindrical casting I2I and fastened thereto by means of the bolts I25. This dome shaped member I24is sealed by means of the lead gasket I26. A cover plate I21 is fastened to the other end of the cylindrical casting I2I by means of cap screws I28 and sealed by means of the lead gasket I29. An electric motor I39 located between the supporting plates I22 and I23 has its stator I3I mounted within the cylindrical casting I2I and its rotor I32 mounted'upon the rotor shaft I33 which in turn is rotatably supported by the bearings I34 and I35. The bearings I34 and I35 are mounted within the bearing housing I36 and I31 which are fixed within the plate members I22 and I23, positioned at either side of the electric motor I39. At one end of the rotor shaft I32 there is provided acrank I38 having a crank pin I39. A ball bearing I49 of any suitable type, such as the self-aligning type, is mounted upon the crank pin I39 by means of the castle nut 149. The outer race of the ball bearing I49 fits within thelower, portion of the piston I42 which has its other end extending into the rotatable cylinder I43. The rotatable cylinder -I43 has a shaft I44 projecting there-- I39 are rotated, the piston is carried along therewith and rotates the cylinder I42 at the same speed as that of the shaft I33. Inasmuch as the cylinder I43 rotates eccentrically with respect to the shaft I33, the piston I42 is caused to reciprocate within the'cylinder I 43.

The' refrigerant gas to be compressedis supplied to the cylinder I43 by means of a conduit I59. The conduit I59 leads to a check valve chamber I5I on the extreme outer part of the spider I41. The check valve I52 is mounted within this chamber I5I and prevents compressed gas from leaking back into the conduit I59 from within the sealed unit. Novel means is provided The crank arm I38, crank pin I 39 and the for supplying and controlling the admission of gas to be compressed from the check valve chamber to the interior of the cylinder I43. A plug I53 is fixed within the plate I54 mounted at the end of the spider I41 and is provided with a central passage and a finger I55 at its innermost end. A chamber I56'is' provided Within the shaft I44. The plug I53 together with its finger I55 extends within this chamber I56. A bellows I51 is sealed at one end to the plug I53 and at the other end to a valve member I58. This valve member I58 is caused to bear against a wearing plate I59 which is fixed in the innermost end of the cavity I56. The wearing plate I59 and the cylinder wall I43 are provided with an inlet port I60 which registers with an inlet passage I6I in the valve member I58 to cause the refrigerant gas to be compressed to be admitted into the interior of the cylinder I43 at the proper time.

An oil pump I55 of the eccentric type is provided at the opposite end of the sealed unit upon the end of the rotor shaft I33. This oil pump draws oil from the lower portion of the sealed from the interior of the sealed unit to enter the unit through the conical strainer I55 and the passage I61 and discharges the oil into the chamber I68 from which the oil forces itself through the drilled passage I59 in the center of the rotor shaft I33. Suitable supply passages I10 and HI supply oil to the bearings I34 and I35. The oil is also supplied through an aperture in the plate I12 to the ball thrust bearing I13 posioil flows through the space surrounding the bellows I51 to the angular passage I18 which leads to a concentric oil groove I19 at the bottom of the wall of the cylinder I43. The passage I80 in the plate I54 leads from the passage in the plug I53 to an oil bleeder I St which opens when the pressure of the oil within the system is excessive. In this modification the oil under pressure in the chamber I68 forces the rotor shaft I33 axially, forcing the crank against the thrust bearing I13 and also forcing the cylinder I43 against a valve plate I68, which during normal running condition, comes to rest on the end of the pin I65.

The gas compressed within the cylinder I43 discharges directly to the interior of the sealed unit. A check Valve cylinder head for controlling the discharge of compressed refrigerant from within the cylinder I43 and for preventing the high pressure gas interior of the cylinder I43. A suitable outlet is provided in the walls of the cylindrical casting I2I for conducting the compressed gas to the conduit leading to the condenser.

In Fig. 6 there is shown a refrigerating system including a sealed motor-compressor unit 220 for compressing the refrigerant and for forwarding the refrigerant through the conduit Hi to a condenser 222 where the refrigerant is condensed and collected in the receiver 223. From the receiver 223 the refrigerant is conducted through the conduit 224 to an expansion valve 225 of any suitable type where the refrigerant under control of a needle valve is allowed I82 is provided in the to pass into the evaporator 226 where the refrigerant expands due to the absorption of heat and is returned to the sealed motor-compressor unit through the return conduit 221. A thermostatically controlled switch 228 is provided for controlling 'the operation of the motor com pressor unit according to the temperature adjacent the evaporator 22 6.

The sealed motor compressor unit 228 is similar in general appearance to the sealed motorcompressor unit shown in Fig. 2 and comprises I a cylindrical casting'239 provided with a central plate 23I and end plates 232 and 233. A cover plate 234 is fastened to one end of the cylindrical and the end' plate 233 is an electric motor 239 having a stator-240 which is fitted within the cylindrical casting 239 held by long bolts 24! which extend through the central plate 23 I stator 249 and are threaded into the end plate 232. The rotor 242 of the electric motor is mounted upon a. rotor shaft 243 which is rotatably mounted within the bearings 244 and 245 which are tightly held within the bearing housings 246 and 241 respectively. A crank arm 248 is fastened to one end of the shaft 243 on,the opposite side of the center plate 23I and is provided with a crank pin 249. Upon the crank pin 249 is mounted a piston 250 which has its head fitting within a rotatable cylinder 25I having a shaft 252 extending from one of its sides and rotat ably mounted within a bearing 253 which is fastened within the bearing housing 254 held by the end plate 233. It should be noted that the rotor shaft 243 and the cylinder shaft 252 are mounted eccentrically with respect'to each other so that when the electric motor rotates the rotor shaft, the crank pin rotates the piston and causes the cylinder to rotate along with it. Because the shafts 243 and 252 are not in alignment the piston 250 will be caused to reciprocate within the cylinder 25I.

This sealed motor-compressor unit differs from the units shown in Figs. 2 and 5 in that the interior of the unit contains refrigerant gas under suction pressure and not under discharge pressure. In this modification the refrigerant gas from the evaporator is drawn into the interior of the sealed unit and is then drawn into the cylinder through the passages in the hollow piston 259. A piston valve 256 controls the admission of this refrigerant gas to be compressed into the interior of the cylinder 25L This valve is preferably of the check valve type. A discharge valve 251 also of the check valve type is provided in the head of the cylinder 25I for controlling the I discharge of compressed gas from the cylinder. The compressed gas discharges through the valve 251 into a discharge chamber 258 provided within the head of the cylinder 25 I, and from this chamber the compressed refrigerant gas is conducted through the passage 259 to a passage 268 which leads to a passage 25'I in the center of the shaft 252. A passage 262 conducts the compressed gas from the passage 26I to a check valve 263 which allows the flow of compressed gas from the passage 263 to the conduit 22I but prevents the return of gas in the conduit22I to the sealed unit.

Lubrication is provided by an oil pump 265 of the eccentric type mounted on the end of the shaft 252 which pumps oil from the bottom of the sealed unit through the conical strainer 233 andthe passage 231 in the plate 233 to a chamber 253 .at the end of the bearing housing 254. From the chamber 253, the oilunder pressure is con- .ducted through the passage 258 to a groove 218 in the lower portion of a wall of the cylinder 25!. This groove 218 lubricates the piston 258 and the walls of the cylinder and also conducts oil to the passage 21!. The oil is then conducted through the passage 21! to an oil passage 212 in the center of the rotor shaft 243. The 011 within the passage 212 is distributed to the oil grooves 213 and 214 to lubricatethe bearings 244 and 245 and also to the groove 215 on the crank pin 248 through the passage 215 in the crank arm.

A novel type of unloader is provided for the compressor. This unloader is placed within the hollow interior of the piston and operates directly upon the inlet valve in the top of the piston 258. A web 211 is provided within the piston for guiding a shaft 218. At one end of the shaft 218 there is provided a guide 218 which is guided by the inner walls of the piston 258. This guide 218 has a plurality of pins projecting therefrom and adapted to move upwardly for holding the inlet valve 255 open. A. spring 288 is provided for forcing the shaft 218, guide 218 and the pins upwardly to hold the inlet valve 255 open. At the other end of the shaft 218 a weight 28! is fixed. When the compressor is at rest, the spring forces the shaft and guide 218 upwardly to hold the inlet valve 255 open. As the compressor begins to rotate the centrifugal force acts upon the weight 23! and this force gradually increases and opposes the action of the spring more and more and finally builds up to a sufllcient amount to remove the pins from the valve 255 and thus allow the valve to close and permit the compressor to begin to compress the refrigerant gas. By this means the compressor starts up without a load and the starting is thereby facilitated- In Fig. '1 the refrigerating system and motor compressor unit are somewhat similar to that shown in Fig. 6 as illustrated. In Fig. '1 there is shown asealed motor compressor unit 328 where refrigerant is compressed and forwarded to a condenser 32! where the refrigerant is liquefied and collected in receiver 322. From the receiver 322 the liquefied refrigerant is conducted to an expansion valve'323 which controls the flow of liquid refrigerant to the evaporator 324 where .the refrigerant vaporizes because of the absorption of heat at its return to the motor compressor unit to the return conduit 325. The operation of the motor-compressor unit is controlled by a thermostatically controlled switch means 325 which controls the operation of the motor-compressor unit according to the temperature adjacent the evaporator 324.

The sealed motor-compressor unit 328 is similar to the unit illustrated in Fig. 6 in that the easing contains refrigerant gas under suction pressure. The sealed unit 328 is constructed of a main cylindrical casting 321 which is provided with a center plate 328 and a pair of end plates 328 and 338. The upper end of the sealed unit 328 is closed by a cover plate 33! which is faste'ned to the cylindrical casting 321 by means of screws 332 and which seals the upper end of the compressor by means of the lead gasket 333. The lower plate 338 is held in position by the clampaoeaus ins ring 334 which is fastened to the cylindrical casting by the screws 335. a

An electric motor 333 1s positioned between the center plate 323 and the end plate 323. The motor 333 comprises a stator 331 which fits within the walls of the cylindrical casting 321 and which is held by long bolts 333 which extend through the center plate 323, stator 331 and are threaded into the upper end plate 323. The rotor 348 is mounted upon a rotor shaft 34! which in turn is rotatably mounted within the bearings 342 and 343 which are fixed within the bearing bosses 344 and 345, east. integral with the end plate 323 and the center plate 323 respectively.

A crank 345 is fastened to the lower end of the rotor shaft 34! and is provided with a crank pin 341. A piston 348 is rotatably mounted upon the crank pin 341 and has its head extending into a rotatable cylinder 345 which has a shaft 358 (see Fig. 9) extending from one of its sides which is rotatably mounted within the bearing 35!. The bearing 35! is fixed within a large bearing boss 352 in the lower end plate 338. The

' piston 348 is provided with a counter weight 353 to balance its massabout the crank pin 341 and the crank arm 345 is also provided with a counter weight 354 having sufllcient mass to balance the return of the crank arm 345 and the crank pin 341 as well as the weight of the piston and counter weight 353. The piston 348 is hollow and is provided with a plurality of apertures 355 which allow the gas in the sealed unit to enter the interior of the piston. From the interior of the piston the gas passes through an inlet valve 355 of the check valve type, mounted in the head of the piston to the interior of the cylinder 348. The gas is compressed in the cylinder 348 and passes through the discharge valve 358, of the check valve type, to a discharge chamber 35! in the head of the cylinder 343. From the discharge chamber 35! at the head of the cylinder 349, the compressed gas is conducted through a passage 352 to a passage 353 in the cylinder shaft 358. From the passage 353 the compressed gas is conducted through the passage 354 to the condenser 32!.

A novel oil pump is provided for circulating the oil to the bearings within the sealed unit. A short oil passage 355 leads to a vertical oil passage 355 in the bearing boss 352. This vertical passage 355 leads to a semi-circular groove 331, better shown in Figs. 9 and 10, which supplies oil to a port 353 in the'lower portion of the wall of the cylinder 348 at proper times. It should be noted that the upper portion of the piston 343 has a slightly smaller diameter than the lower portion and in the same way the interior diameter of the upper portion of the cylinder 345 has a slightly smaller diameter than the lower portion in the same way so that there are diiferences in diameter in the piston 348. This piston may therefore be described as a stepped or double diameter piston and the cylinder described similarly. By providing a piston and cylinder of this contour, a pumping chamber 353 is provided for pumping the oil. The port 353 registers with the groove 351 at proper times to allow oil to be drawn into the pumping chamber 358 and the oil is then forced from the pumping chamber 358 through the discharge port 318 which registers with a suitable port 31! in the crank arm 345 at proper times to supply oil to the oil passage 312 in the crank arm. The passage 312 supplies oil to the passage 313 in the crank am 341 and also supplies oil to the oil pressor back into the conduit 429.

passage 314 in the central portion of the rotor shaft 84!. The passage 314 conducts the oil to the bearings 342 and 343.

The modification shown in Fig. 12 contains most all of the desirable features of novelty of that shown in the other modifications. This figure shows a compressor of the rotating cylinder type having a crank arm 420 provided with a crank pin 428 upon which a hollow piston 422 is mounted. The head of the hollow piston 422 fitswithin the rotatable cylinder 423 and has a hollow shaft 424 extending from one side thereof which is mounted within the bearing 425 fixed within a boss 426 upon the spider 427. This the hollow shaft 424 and has a thrust finger 436 extending upwardly therefrom. A bellows 431 is sealed to a shoulder on the plug 432 and has a valve member 433 connected to its upper end which bears against the end of the chamber 435.

The valve member 438 has a passage 439 therein which, at proper times, allows the gas within the plug 432 and the bellows 43? to flow through the passage 44!? in the wall of the cylinder 432 to the compressing chamber of the cylinder 423. The piston 422 will be reciprocated within the cylinder 423 by reason of the fact that the crank 425 and the cylinder 423 are mounted eccentrically of each other. The reciprocation of the piston causes the gas to be compressed and to be forced out of the cylinder past the discharge valve 44L of the check valve type, to the interior of the sealed unit from which it is cone ducted to the condenser.

It will be noted that this modification is provided with the double diameter oil pump in which the piston 422 is provided with an upper portion of a smaller diameter and the cylinder 423 is provided with a portion nearest the head with a smaller diameter corresponding to the diameter of the piston. A pumping chamber 444 is provided between the largediameter portion and the small diameter portion of the cylinder and piston. The oil is drawn by this pumping chamher through an oil tube 445 through the passage 445 to the chamber 447?. From the chamber 441 the oil passes through the passage between the bellows 43? and the outer portion of the chamber 455 on its way to the inlet valve 448, of the check valve type, which permits the flow of oil into the pumping chamber 444 but prevents the flow of oil from the pumping chamber back to the chamber 435. The valve 443, also of thecheck valve type, is provided on the opposite side of thecylinder 423 and permits the oil to how from the pumping chamber into the oil passages 450 the piston. A plurality of pins 455 extend from 451 in the piston 422. A coil spring 458 urges the guide 455 toward the head of the piston to open the valve 451. At theother end of the rod 454 a'weight 459 is provided which, is acted upon by centrifugal force when the compressor begins to rotate. When the compressor is at rest the coil spring 458 will hold the valve 451 open. When the compressor begins to rotate the centrifugal force acts upon the weight 459 and opposes the spring 458. As the speed of the compressor increases the force upon the weight 459 increases and becomes greater than the force of the spring 458 and for this reason causes the valve to be pulled shut. In thisway the compressor is unloaded when at rest and until it attains suflicient speed.

While the form of embodiment of the invene 'tion asherein disclosed constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

What is claimed is as follows: I 1. Refrigerating 'apparatus including a sealed unit containing a compressor, said compressor having a cylinder rotatably mounted within the sealed unit, a rotatable crankshaft eccentrically mounted with respect to said rotatable cylinder, a crankpin upon said crankshaft, a piston within said cylinder, said piston having an end projecting from the cylinder and a bearing within said end rotatably mounted upon said crankpin, said piston having a plurality of diameters and said cylinder having a plurality of diameters corresponding to said piston forming a plurality of pumping chambers, a valve in said piston leading to one of said pumping chambers, un-

loading means for holding said valve in said piston open when the compressor rotates below a certain speed including a spring for urging said valve to open position and centrifugally actuated means for removing said holding means from holding position including a weight actuated by centrifugal force to oppose the force of said spring, an inlet port for one of the pumping chambers of said cylinder, a stationary valve plate for controlling the flow of fluid to said inlet port, a bellows connected to said valve plate, said valve plate and bellows being situated within a chamfiuid to be pumped to the interior of said bellows, means for conducting lubricant to be pumped to the chamber surrounding said bellows, means for conducting said lubricant from said last mentioned chamber to another of said pumping chambers; and means for conducting the lubricant from the pumping chambers to the bearing surfaces of said compressor.

2. Refrigerating apparatus including a sealed unit containing a compressor, said compressor having a cylinder rotatably mounted within said sealed unit about a first axis, a piston within said cylinder rotatably mounted about -a second axis, a port for said cylinder, a valve plate having means for controlling the supply of fluid for said port, a bellows connected to said valve plate for maintaining said valve plate in proper position, means for sealing the bellows, means for conducting. compressible fluid on one side of said bellows, means for conducting lubricant on the other side of said bellows and discharge means for said cylinder.

3. Refrigerating apparatus including a sealed unit containing a compressor; said compressor having a cylinder rotatably mounted on a bearing within said sealed unit, a piston within said cylinder rotatably mounted on a second best-in: compressible fluid on one side of said bellows, eccentric to said first named bearing, a port !or means for conducting lubricant for one of said said cylinder, a. valve plate having means for hearings on the other side or said bellows, and controlling the supply of fluid for said port. a discharge means for said cylinder.

bellows connected to slid valve plate for maintaming said valve plate in proper position, means f HARRY B. HULL.

i'orsealing the bellows, means'for oonducflng ALEX A. McCORMACE- 

